What the Anesthesiologist Should Know before the Operative Procedure

Breast cancer is the second leading cause of cancer death in women, and In the United States, over a lifetime, 1 in 8 women will be diagnosed with breast cancer and 1 in 35 will die from the disease. In contrast, male breast cancer is rare, accounting for approximately 1% of male cancers. Mastectomy, the removal of one or both breasts, is the local treatment for breast cancer and may be combined with adjuvant treatments including radiation, chemotherapy, or hormone therapy. Mastectomy may be subdivided into:

Nipple sparing: removal of breast tissue with preservation of the nipple-areola complex

Modified radical: a simple mastectomy and removal of level I and II axillary lymph nodes

Radical mastectomy: removal of the entire breast, axillary lymph nodes, and both pectoralis major and minor muscles

The type of mastectomy performed depends on several factors, including size of the tumor, number of lesions, tumor type, and invasiveness (skin, axilla, underlying muscle) as well as patient preference. For patients with mutations of the BRCA genes, who have a greatly increased risk of developing breast cancer, mastectomy may be performed prophylactically. Reconstruction of the breast may immediately follow mastectomy or may be planned as a delayed procedure.

Breast cancer incidence increases with age, with most women presenting in their 6th and 7th decades, and therefore, significant comorbidities may be present that may require optimization prior to surgery. Typically, patients are admitted to the hospital postoperatively for 1 to 2 days' observation, although simple mastectomy may be performed on an ambulatory basis provided that pain and nausea (the most common postoperative complications) are managed adequately.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Mastectomy is rarely an emergent or urgent procedure, although delay of the procedure much beyond the period of diagnosis theoretically increases the risk of metastases and spread of disease. Mastectomy is only truly elective if it is performed as a prophylactic procedure.

Emergent: if the cancer has developed into a fungating wound with concomitant sepsis or risk for significant bleeding or sepsis

Urgent: if there is increased risk for growth and spread of the disease (i.e., pregnancy with hormonal stimulation)

Elective: for breast cancer prophylaxis

2. Preoperative evaluation

Assessment of the patient should include a careful review of the medical history, including comorbid conditions, medications, and drug allergies in order to allow for perioperative and postoperative risk stratification. Evaluation for metastatic disease should be carried out to determine effects on organ systems, particularly spinal cord, lung, and brain. Review of previous chemotherapy treatments is important to identify any residual toxicities including anemia and doxorubicin cardiotoxicity. As mastectomy is rarely an emergent or truly urgent procedure, any uncontrolled medical condition or new pathology should be appropriately evaluated and treated prior to surgery.

Baseline coronary artery disease or cardiac dysfunction Goals of management: Mastectomy is considered a low-risk procedure, and therefore, assessment of a patient's functional status and severity of disease is necessary in order to properly risk stratify. Careful questioning to ascertain any changes in symptoms (chest pain, dyspnea, decreased exercise tolerance), medication changes, recent interventions or hospitalizations should be performed, and prior ECG, cardiac testing (noninvasive stress testing, catheterizations, echo) and laboratory data should be reviewed. Unless unstable or active cardiac conditions are present, further workup or intervention has not been shown to alter outcome.

Perioperative Risk Reduction Strategies

Monitoring- the need for invasive monitoring (arterial line, CVP, PA catheter, TEE) must be balanced against disease severity and risks of line placement. Given the low risk nature of mastectomy, the lack of significant blood loss or hemodynamic instability, the need for invasive monitoring is rare.

Goals

Balance oxygen supply and demand

Increase supply

Increase the fraction of inspired oxygen concentration (FiO2)

Increase oxygen-carrying capacity (hemoglobin)

Avoid tachycardia, which reduces the time spent in diastole and LV perfusion

c. Pulmonary

Patients with pulmonary disease are at increased risk of postoperative pneumonia and dysfunction after general anesthesia. Metastases to the lung may result in pleural effusions and parenchymal invasion which may compromise pulmonary function.

COPD

Preoperative evaluation

A careful clinical history should be obtained, which includes smoking history, symptoms (dyspnea, exercise tolerance), frequency of exacerbations, oxygen requirements, prior hospitalizations or intubations, steroid use, current medication regimen, and any available pulmonary studies. Although PFTs are a useful measure of severity of disease and response to bronchodilators, they have not been shown to alter outcome for low-risk procedures.

Perioperative risk reduction strategies

Continue current pulmonary medications perioperatively.

Treat any underlying respiratory infections or exacerbations.

Counsel patient to cease smoking to reduce airway irritability, if able to discontinue 6-8 weeks prior to surgery.

A regional anesthetic (thoracic epidural or paravertebral block) may allow for improved analgesia and reduction of postoperative atelectasis (decreased splinting and more effective cough). Since a high thoracic level (T2-6) is required, the technique may not be best suited for pulmonary cripples who depend on accessory muscles to breathe.

If a general anesthetic is used, mechanical ventilation should be optimized by adjusting the I:E ratio to allow for adequate expiratory time, reducing the respiratory rate, increasing FiO2, adding PEEP, using bronchodilators and humidifying gases. Deep extubation should be considered if appropriate to avoid triggering bronchospasm.

Reactive airway disease (asthma)

Preoperative Evaluation

Review of the clinical history to assess severity of disease, frequency of exacerbations, triggers, current medical regimen, use of steroids, and any hospitalizations and intubations.

Chronic Renal insufficiency may result in metabolic disturbances including hyperkalemia, hypocalcemia, hyperphosphatemia, metabolic acidosis, fluid overload and pulmonary edema, and anemia. Medications and dialysis history should be reviewed, and baseline laboratory data obtained.

Perioperative risk reduction strategies

Avoid nephrotoxins, drugs such as aminoglycosides and NSAIDs.

Avoid drugs that depend on renal excretion for elimination.

Avoid hypotension, hypoxia, and dehydration, which may decrease renal perfusion.

f. Endocrine:

Preoperative evaluation

A careful history should be obtained to evaluate for any preexisting endocrine disease such as diabetes, thyroid disease, or pituitary axis disorders. Laboratory date should be reviewed including electrolytes, serum glucose, HbA1c, thyroid studies.

Perioperative risk reduction strategies

Normoglycemia should be maintained in the perioperative period, and may reduce perioperative infection rate, and improve healing. Hormone replacement or suppressant medications should be continued in the perioperative period.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

N/A

4. What are the patient's medications and how should they be managed in the perioperative period?

N/A

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

This may include medications specific to diseases associated with surgery. Chemotherapuetic agents: Doxorubicin (Adriamycin) is frequently administered to breast cancer patients, and may result in cardiomyopathy. Patients are evaluated prior to treatment with either MUGA scan or echo to assess for preexisting abnormalities. These studies should be reviewed, and if clinical history is suspicious for Adriamycin-induced cardiac dysfunction (dyspnea, cough, decreased exercise tolerance, arrhythmias), further evaluation should occur prior to surgery.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac:

Beta-blockers and antihypertensive drugs should be continued in the perioperative period. Consider holding diuretics, ACE inhibitors and ARBs on the day of surgery to avoid intraoperative hypotension. Anticoagulants and aspirin are typically held 5-7 days prior to surgery. For patients with cardiac stents, the optimal management of antiplatelet drugs should be discussed with the cardiologist and surgeon in order to balance the risk of thrombosis against increased surgical bleeding.

A clean anesthesia machine must be used. If an MH-specific machine is not available, then the machine should be flushed with high oxygen flow rates for at least 20 minutes, and all tubing and the CO2 absorbent should be replaced.

Family history or risk factors for MH: The above precautions should be taken with patients who have a positive family history, history of central core disease, myopathy, or Duchenne's muscular dystrophy.

Local anesthetics/ muscle relaxants

Allergic reactions to local anesthetics are rare, and typically to the ester local anesthetics. Avoidance of these agents and substitution with an amide local anesthetic is appropriate.

5. What laboratory tests should be obtained and has everything been reviewed?

Simple mastectomy is a low-risk procedure and is generally performed in relatively healthy women. Therefore, no preoperative laboratory testing is necessary, and it should be dictated on the basis of consideration of preexisting medical conditions. A radical mastectomy has the potential for significant blood loss, and obtaining a preoperative hemoglobin and blood bank sample would be prudent.

Additional testing may be necessary depending on the patient's coexisting medical conditions.

Hemoglobin levels:

May consider a preoperative hemoglobin level in patients with history of bleeding, recent chemotherapy or radiation therapy, anemia, and renal failure.

Electrolytes:

May consider obtaining preoperative values in patients on chronic diuretics and steroids, patients with a history of renal insufficiency and dialysis.

Coagulation panel:

Consider obtaining in patients with a history of bleeding abnormalities or liver disease and those taking anticoagulants.

Imaging:

Need for chest radiograph and ECG should be dictated by clinical history.

Other tests:

Additional testing should be dictated by clinical history (e.g., TSH in patients suspected for thyroid disease beta-HCG for patients who may be pregnant).

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

Simple mastectomy may be performed under general or regional anesthesia, or combined technique.

Regional anesthesia

May be performed with sedation or combined with a general anesthetic to provide postoperative analgesia.

Neuraxial

The breast is innervated by the anterior cutaneous branches of Intercostal nerves 1-6 (T1-6) and the lateral cutaneous branches of intercostal nerves 2-7 (T2-7), therefore a high thoracic epidural may be utilized for the anesthetic or for postoperative analgesia. If axillary dissection is to be undertaken, additional blockade of the lower cervical roots may be required (superficial cervical plexus block).

Benefits

Thoracic epidural for mastectomy is associated with reduced postoperative nausea and vomiting, improved analgesia, and possibly shorter hospital stay when compared to general anesthesia

Avoidance of airway manipulation and triggering of bronchospasm in patients at significant risk

Drawbacks

Contraindicated in patients on anticoagulants (ASRA guidelines should be followed)

Sympathectomy may not be well tolerated in patients with CAD, valvular lesions and cerebrovascular disease

Patients may not be able to tolerate the psychological distress of mastectomy under light sedation if used as the sole anesthetic.

Local anesthetic supplementation may be necessary for inadequate dermatomal coverage, and axillary dissection

May not be appropriate for patients with pulmonary compromise who require accessory muscle use

Peripheral nerve block

The paravertebral block may be utilized as the sole anesthetic or combined with general anesthesia to provide perioperative analgesia, and may be performed unilaterally or bilaterally. The same considerations as for epidural apply.

Benefits

Improved analgesia when compared to general anesthesia alone

Reduced PONV when compared to general anesthesia alone

Greater patient satisfaction when compared to general anesthesia alone

b. General Anesthesia

May be used as the sole anesthetic or combined with a regional technique.

Benefits

Provides for a secure airway and management of pulmonary mechanics

May be better tolerated psychologically

Better tolerance for longer procedures

Avoids risks of regional techniques

An LMA can be utilized to reduce airway irritability if muscle relaxation is not required for immediate reconstruction procedures

Drawbacks

Higher incidence of PONV compared to regional techniques

Less patient satisfaction compared to regional techniques

Hemodynamic swings

Risk for pulmonary aspiration

Risk for postoperative myalgias with use of depolarizing muscle relaxants

c. Monitored Anesthesia Care

Not adequate as the sole anesthetic technique for this procedure.

6. What is the author's preferred method of anesthesia technique and why?

Combined paravertebral block and general anesthetic is our preferred method of anesthesia for mastectomy as it results in excellent perioperative analgesia, a reduction in the incidence of PONV, greater patient satisfaction, and the potential for earlier hospital discharge. The paravertebral block is a safe and effective technique when performed by an experienced practitioner, and avoids the complications associated with a high thoracic epidural. Currently there is great interest in regional techniques for mastectomy as a result of literature that suggests a possible reduced recurrence rate of disease. Utilizing 0.5% bupivacaine in volumes of 15 to 40 mL, an average block duration of 16 hours can be obtained. Postoperatively patients are supplemented with parenteral narcotics as needed, and are usually transitioned to oral analgesics on postoperative day 1.

What prophylactic antibiotics should be administered?

A cephalosporin is typically administered within 30 minutes of the procedure. A suitable alternative is chosen if the patient has a history of penicillin or cephalosporin allergy.

What do I need to know about the surgical technique to optimize my anesthetic care?

Mastectomy ranges from simple to radical (as described above), and the more invasive procedures (axillary dissection and removal of chest muscle) may be associated with greater blood loss. However, the type of mastectomy should not impact the anesthetic management.

Mastectomy with immediate reconstruction: Placement of tissue expanders or implants under the pectoralis muscle often requires muscle relaxation by the plastic surgeon. During axillary dissection, however, the surgeon may want to avoid muscle relaxation in order to avoid injury to the brachial plexus. This should be considered when planning airway management and muscle relaxant use.

What can I do intraoperatively to assist the surgeon and optimize patient care?

Communicate with the surgeon to determine muscle relaxant needs.

What are the most common intraoperative complications and how can they be avoided/treated?

Hypotension due to sympathectomy and preoperative dehydration. Adequate fluid resuscitation and vasoconstrictor (ephedrine, phenylephrine) administration are usually sufficient to manage the issue.

a. Neurologic: *** Type Here.

N/A

b. If the patient is intubated, are there any special criteria for extubation?

The standard criteria for extubation should be followed.

c. Postoperative management

What analgesic modalities can I implement?

What level bed acuity is appropriate?

Bed acuity depends on patient's perioperative condition, intraoperative course, and hospital resources. The patient is typically discharged from the PACU to a standard floor bed. Unilateral simple mastectomy may be performed on an ambulatory basis.

What are common postoperative complications, and ways to prevent and treat them?

(Meta-analysis of 15 RCT’s providing evidence to support superiority of paravertebral block in addition to general anesthesia or alone in providing postoperative pain control with fewer adverse effects in breast surgery.)